Microbiological control in aqueous systems

Abstract

Microbiological control is achieved by continuously and inexpensively dosing water in contact with biofilm, or that comes into contact with biofilm, using a highly effective biocide that provides very effective microbiocidal control of planktonic microorganisms and of biofilm species, even where the biofilm infestations have been in existence for long periods of time and thus have encased themselves in a substantial quantity of slimy defensive polysaccharide layers or films. In addition, the biocide used makes possible significant reduction in copper and/or iron surfaces in contact with the water as compared to N,N′-bromochloro-5,5-dimethyl hydantoin. Still other advantages are made possible by the described technology.

1. A water sanitizer which comprises a dispenser that automatically dispenses a sanitizing chemical into water at a controlled rate, said dispenser containing a charge of at least one 1,3-dibromo-5,5-dialkylhydantoin, in which one of the alkyl groups in the 5-position is a methyl group and in which the other alkyl group in the 5-position has in the range of 1 to 4 carbon atoms, that as charged thereto is in the form of granules free of hydrophobic binder, and devoid of any additive therein conferring binding or hardening action to said granules, which granules have an average crush strength of at least 15 pounds per inch of granule thickness, and an average size in the range of about 40 U.S. standard mesh size to about ⅜-inch, said dispenser being adapted to dispense dissolved biocide species from said at least one 1,3-dibromo-5,5-dialkylhydantoin at a rate that maintains a biocidally effective amount of “free chlorine” in said water. 
     
     
       2. A water sanitizer according to  claim 1  wherein said average crush strength is at least 20 pounds per inch of granule thickness. 
     
     
       3. A water sanitizer according to  claim 1  wherein said at least one 1,3-dibromo-5,5-dialkylhydantoin is 1,3-dibromo-5,5-dialkylhydantoin and wherein said granules are able to be dissolved in quiescent water that is at a temperature of 25° C. at a rate such that 60 minutes after immersing said granules in quiescent water, the water contains in the range of about 75 to about 430 mg/L of “free chlorine” per gram of granules that were immersed in the water. 
     
     
       4. A water sanitizer according to  claim 3  wherein said average crush strength is at least 20 pounds per inch of granule thickness.